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Biomedical subjects

B U Bender

Publications and source records attributed to B U Bender.

16 recordsLinked to original sources
PubMed2003

Haemolytic uraemic syndrome and mutations of the factor H gene: a registry-based study of German speaking countries.

BACKGROUND: The aetiology of atypical haemolytic uraemic syndrome (aHUS) is, in contrast to classical, Shiga-like toxin induced HUS in children, largely unknown. Deficiency of human complement factor H and familial occurrence led to identification of the factor H gene (FH1) as the susceptibility gene, but the frequency and relevance of FH1 mutations are unknown. METHODS: We established a German registry for aHUS and analysed in all patients and 100 controls the complete FH1 gene by single strand confirmational polymorphism and DNA sequencing. In addition, complement C3 and factor H serum levels were assayed. Demographic data at onset of aHUS and follow up were compared for the mutation positive and negative groups. RESULTS: Of 111 patients with aHUS (68 female, 43 male, mean age 33 years) 14% had FH1 germline mutations, including two of eight patients with familial aHUS. For each of these eight patients, both parents were tested, and we were able to trace the mutation for five cases. In the other three cases (one with the mutation 3749 C/T, one with 3200 T/C, and one with 3566+1 G/A), we could not detect the mutation in either parent, although paternity was proven by genetic fingerprinting, suggesting that these subjects have new mutations. C3 was decreased in five mutation carriers but also in two non-carriers, and factor H was decreased in none of the carriers, but elevated in six carriers and 15 non-carriers. Clinical parameters including associated medications and diseases, and outcome of aHUS and of post-aHUS kidney transplantation were similar in the mutation positive and negative groups. CONCLUSION: FH1 germline mutations occur with considerable frequency in patients with aHUS. Hypocomplementaemia is not regularly associated with a germline mutation, and factor H serum levels can even be elevated. Screening for FH1 mutations contributes to the classification of aHUS.

Adult↗
PubMed2001

VHL c.505 T>C mutation confers a high age related penetrance but no increased overall mortality.

BACKGROUND: Germline mutations of the VHL gene cause von Hippel-Lindau syndrome (VHL). In southern Germany, a specific mutation in this gene, c.505 T>C, is one of the most frequent alterations owing to a founder effect. METHODS: This study was conducted to evaluate morbidity, specific clinical risk profile, and mortality among a series of VHL c.505 T/C mutation carriers. A total of 125 eligible subjects carrying VHL c.505 T/C underwent ophthalmoscopy and gadolinium enhanced magnetic resonance imaging of the brain, the spinal cord, and the abdomen. Age related penetrance, morbidity, and mortality were assessed. RESULTS: Frequently observed lesions were phaeochromocytoma (47%), retinal angiomas (36%), haemangioblastoma of the spine (36%), and haemangioblastoma of the brain (16%). Four patients developed renal cell carcinoma. VHL was symptomatic in 47% of subjects; 30% were asymptomatic despite the presence of at least one VHL related tumour and 23% of the carriers had no detectable VHL lesion. Of the 19 patients who had died (15%), 10 died of symptomatic VHL lesions. Overall penetrance by cumulative incidence functions is estimated at 48% by 35 years and 88% by 70 years. In contrast to the only existing published report based on patients with presumably unselected VHL germline mutations, the mortality rate for c.505 T/C mutation carriers is comparable to that of the general population of Germany. CONCLUSIONS: Our results are an important example that a specific genotype, at least in the case of VHL c.505 T/C, can favourably impact on mortality despite a high age related penetrance. Our study also indirectly provides objective data which might be useful to the life and health insurance industry; it would appear that c.505 T>C mutation positive subjects have similar disease specific mortality to that of the general population owing to a combination of phenotype and timely detection of mutation carrier status followed by aggressive clinical screening and, if necessary, treatment.

Adolescent↗
PubMed2001

Reconsideration of biallelic inactivation of the VHL tumour suppressor gene in hemangioblastomas of the central nervous system.

OBJECTIVES: Cerebellar haemangioblastoma occurs sporadically or as a component tumour of autosomal dominant von Hippel-Lindau disease. Biallelic inactivation of the VHL tumour suppressor gene, which is located on chromosome 3p, has been shown to be involved in the pathogenesis of both tumour entities. Mechanisms of VHL inactivation are intragenic mutations, mitotic recombination events, and hypermethylation of the promoter region. The systematic and complete examination of these genetic and epigenetic phenomena in large series of von Hippel-Lindau disease related and sporadic hemangioblastomas has, thus far, not been performed. METHODS: In the largest series to date, 29 von Hippel-Lindau disease associated and 13 sporadic haemangioblastomas were investigated for all suggested inactivating mechanisms of the VHL gene using single strand conformational polymorphism (SSCP), loss of heterozygosity (LOH), and methylation analyses. Additionally, corresponding blood samples of all patients were screened for VHL germline mutations by SSCP and Southern blotting. RESULTS: Germline mutations were identified in 94% of patients with von Hippel-Lindau disease and their tumours and 62% of these hemangioblastomas showed LOH of chromosome 3p. Of the 13 sporadic tumours, 23% showed a single somatic mutation of the VHL gene that was not present in the germline. 3p LOH was identified in 50% of informative sporadic tumours. No von Hippel-Lindau disease related or sporadic tumour demonstrated VHL promoter hypermethylation. CONCLUSIONS: For most von Hippel-Lindau disease related haemangioblastomas, the inactivation or loss of both alleles of the VHL gene, as predicted by the Knudson two hit theory, is required. However, in a subset of tumours including most sporadic haemangioblastomas, the genetic pathways involved in tumorigenesis have yet to be defined and may represent alterations of a different pathway or pathways.

Adolescent↗
PubMed2000

Differential genetic alterations in von Hippel-Lindau syndrome-associated and sporadic pheochromocytomas.

Pheochromocytomas arise sporadically and as a component tumor of the inherited cancer syndromes von Hippel-Lindau disease (VHL), multiple endocrine neoplasia type 2 (MEN 2), and type 1 neurofibromatosis. Germline mutations of the VHL tumor suppressor gene (VHL) are responsible for VHL, and germline RET protooncogene mutations are associated with MEN 2. The present study was conducted to examine a large series of 36 VHL-related pheochromocytomas for somatic VHL and RET gene alterations and loss of heterozygosity (LOH) of markers on chromosome arms 1p, 3p, and 22q. For comparison, the same analyses were performed in 17 sporadic pheochromocytomas. We found no somatic intragenic mutations within VHL and RET in any VHL or sporadic pheochromocytoma, and no pheochromocytoma demonstrated upstream VHL gene hypermethylation. Of interest, we found significantly different LOH frequencies at 3 loci between sporadic and VHL tumors; the more than 91% LOH of markers on 3p and the relatively low frequencies of LOH at 1p and 22q (15% and 21%, respectively) in VHL pheochromocytomas argue for the importance of VHL gene dysregulation and dysfunction in the pathogenesis of almost all VHL pheochromocytomas. In contrast, the relatively low frequency of 3p LOH (24%; P: << 0.0001) and the lack of intragenic VHL alterations compared with the high frequency of 1p LOH (71%; P: = 0.0003) and the moderate frequency of 22q LOH (53%) in sporadic pheochromocytomas argue for genes other than VHL, especially on 1p, that are significant for sporadic tumorigenesis and suggest that the genetic pathways involved in sporadic vs. VHL pheochromocytoma genesis are distinct.

Adrenal Gland Neoplasms↗
PubMed1999

[Retinal capillary angioma. Clinical and molecular genetic studies].

UNLABELLED: Capillary retinal angiomas are rare vascular tumors that frequently occur in von Hippel-Lindau syndrome (vHL) but may also be sporadic. In all patients presenting with this tumor a thorough search for other vHL-associated lesions must be performed. After identification of the vHL gene on the short arm of chromosome 3 (3p25-26), the diagnosis is supported by molecular genetic analysis. PATIENTS: In 20 patients with retinal angioma a clinical search for other manifestations of vHL was performed. In 5 patients only one angioma was present. In all patients molecular genetic tests for a mutation of the vHL gene were performed by SSCP and direct sequencing. RESULTS: In 16 (80%) patients vHl was present, and in 15 it could be diagnosed by clinical findings or a positive family history. Organ lesions in vHL patients were CNS hemangioblastoma in 10 (63%), pancreatic cysts in 7 (43%) and renal cysts in 7 (43%) patients. In two patients (13%) renal carcinoma could be detected; in one patient a pheochromocytoma was present. A mutation could be detected in all 15 patients with clinically confirmed vHL. In three patients a new mutation of vHL disease was diagnosed genetically. In one of these patients a single retinal angioma was the only sign of vHL. CONCLUSION: In patients presenting with capillary retinal angioma a careful search for other vHL lesions has to be performed. A mutation of the vHL gene can be detected in the majority of patients; thus, molecular genetic testing is a powerful tool for diagnosis and detection of asymptomatic gene-carriers.

Adolescent↗
PubMed1999

Adrenal-sparing surgery for phaeochromocytoma.

BACKGROUND: Adrenalectomy is the current treatment for phaeochromocytoma. Consequently, patients with bilateral adrenal phaeochromocytoma become steroid dependent. An adrenal-sparing surgical technique was introduced in 1985. The results of this treatment have been reviewed. METHODS: Since 1985, 39 patients with adrenal phaeochromocytoma (16 men and 23 women, aged 10-76 years) have been treated. Thirty-three patients had unilateral and six had bilateral phaeochromocytomas. Seven of the former 33 had a contralateral adrenal tumour resected previously. All 39 patients were re-evaluated biochemically and clinically for ipsilateral recurrence. RESULTS: Adrenal-sparing surgery was performed successfully in 37 of the 39 patients. In one, adrenal-sparing resection was impossible anatomically and total adrenalectomy was necessary. Another patient with bilateral tumours had retroperitoneal haemorrhage and became steroid dependent. None of the remaining 12 patients who had bilateral adrenal surgery required steroid replacement. Adrenocortical function was normal in eight and mildly impaired in two of the ten patients who had evaluation by adrenocorticotrophic hormone stimulation. After a mean follow-up of 73 months, one patient with von Hippel-Lindau disease developed a recurrence in the ipsilateral adrenal gland. Genetic testing revealed that 26 of the 39 patients, including half of those with a unilateral tumour, had hereditary phaeochromocytoma. CONCLUSION: Adrenal-sparing surgery is safe and effective, and may become the treatment of choice in patients with hereditary phaeochromocytoma.

Adolescent↗
PubMed1999

The impact of molecular genetic analysis of the VHL gene in patients with haemangioblastomas of the central nervous system.

OBJECTIVES: Haemangioblastoma of the CNS occurs as a sporadic entity and as a manifestation of the autosomal dominant von Hippel-Lindau disease with the major additional components retinal angioma, renal cancer, and pheochromocytoma. Genetic testing for germline mutations predisposing to von Hippel-Lindau disease has been available since identification of the VHL tumour suppressor gene. The impact of this testing was evaluated in patients with haemangioblastomas seen in this centre. METHODS: A register and database of patients with symptomatic haemangioblastomas for the last 15 years was evaluated. The VHL gene was analysed by the SSCP method for all exons and Southern blotting for mutations and deletions of the gene. RESULTS: 141 patients with haemangioblastoma of the CNS were registered. In 81 patients (57%) there was a disease predisposing germline mutation including eight novel mutations. Population related calculation of patients from the administrative district of Freiburg disclosed VHL germline mutations in 22% of the patients with haemangioblastoma. Analysis of mutation carriers for clinical information suggestive of the syndrome showed (1) a positive family history of a brain tumour in 50%, (2) a history for the patient of extracranial manifestations in 36% (retinal angioma 30%, pheochromocytoma 6%), and (3) 19% presenting with multiple brain tumours when first admitted. By genetic testing of haemangioblastoma patients without any indications of von Hippel-Lindau disease mutation carriers were identified in 14%. Sensitivity of VHL germline testing was 86%. CONCLUSIONS: DNA analysis for VHL germline mutations is clearly superior to clinical information in the diagnosis of von Hippel-Lindau disease. Although the percentage of von Hippel-Lindau disease associated haemangioblastoma decreases after the fourth decade of life and is infrequent in patients without other symptomatic lesions and a negative family history, it is recommended that every patient with CNS haemangioblastoma should be screened for von Hippel-Lindau disease germline mutations. This provides the key information and enables screening for extraneurological tumours of the patients and investigations of the patient's family to ameliorate management of von Hippel-Lindau disease.

Adolescent↗
PubMed1999

Preserved adrenocortical function after laparoscopic bilateral adrenal sparing surgery for hereditary pheochromocytoma.

BACKGROUND: Familial pheochromocytoma, increasingly diagnosed in asymptomatic subjects with inherited syndromes such as multiple endocrine neoplasia type 2 and Von Hippel-Lindau disease, is frequently bilateral and multifocal, but very rarely malignant. Therefore, bilateral adrenalectomy and subsequent lifelong steroid replacement, with its attendant side effects, is not desirable. Minimally invasive adrenal sparing surgery by means of laparoscopy was explored for the treatment of bilateral pheochromocytoma. We report on the cure rate and adrenocortical function in a series of patients treated accordingly. PATIENTS AND METHODS: Four patients (three male, one female, ages 9-60 yr) with hereditary bilateral adrenal pheochromocytoma were treated by laparoscopic surgery in an organ sparing fashion. Postoperatively, all patients were reevaluated for complete tumor removal and for adrenocortical function. RESULTS: Two to 24 months after surgery, all patients were normotensive, had normal sodium potassium, glucose, aldosterone, renin, and cortisol serum concentrations, 24-h excretion of norepinephrine, epinephrine, and vanillylmandelic acid. Abdominal magnetic resonance imaging (n = 3) and computed tomographic scan (n = 1) disclosed no remnant or relapsing tumor tissue. ACTH stimulation testing resulted in normal cortisol responses. CONCLUSION: By adrenal sparing laparoscopic surgery not only bilateral pheochromocytoma can be successfully removed, but also adrenocortical function preserved. This may become the treatment of choice for familial pheochromocytoma.

Adrenal Cortex↗
PubMed1998

Genotype-phenotype correlations in von Hippel-Lindau disease.

A total of 146 intragenic germline mutations of the von Hippel-Lindau (VHL) gene are known and this figure is still increasing. To date, information for mutation-specific genetic counselling is insufficient, since either the total number of carriers is very low or clinical information and investigation of symptomatic and asymptomatic is incomplete. This review summarizes all known mutations and includes the centres which performed the mutation analyses and may provide further information regarding specific mutations.

Genetic Counseling↗
PubMed1998

Prevalence, morphology and biology of renal cell carcinoma in von Hippel-Lindau disease compared to sporadic renal cell carcinoma.

PURPOSE: Renal cell carcinoma occurs as a sporadic tumor but may be part of the autosomal dominant von Hippel-Lindau disease, characterized by retinal and central nervous system hemangioblastoma, pheochromocytoma, pancreatic cysts and renal cell carcinoma. We determine the prevalence of von Hippel-Lindau disease in a series of unselected renal cell carcinoma cases by molecular genetic analysis, and compare sporadic to von Hippel-Lindau renal cell carcinoma with respect to morphology and biology. MATERIALS AND METHODS: We established registers comprising 63 subjects with von Hippel-Lindau renal cell carcinoma, belonging to 30 distinct families (register A), and 460 unselected patients operated on for renal cell carcinoma in an 11-year period (register B). Molecular genetic analysis of the von Hippel-Lindau gene was performed for living patients of register A, representing 80% of von Hippel-Lindau families, and register B, 62% living patients, to identify von Hippel-Lindau germline mutations. In addition, register B was evaluated by a questionnaire (95% response) for familial occurrence of von Hippel-Lindau disease. RESULTS: The prevalence of von Hippel-Lindau renal cell carcinoma was 1.6% in 189 consenting unselected renal cell carcinoma patients. Risk factors for occult germline von Hippel-Lindau gene mutations in register B included familial renal cell carcinoma in 3 of 3 patients (100%), multifocal or bilateral renal cell carcinoma in 1 of 10 (10%) and age younger than 50 years at diagnosis in 1 of 33 (3%). Compared to sporadic von Hippel-Lindau renal cell carcinoma was characterized by an occurrence 25 years earlier, association with renal cysts, multifocal and bilateral tumors, cystic organization and low grade histology, and a better 10-year survival (p < 0.001 each). In von Hippel-Lindau disease metastases occurred only in tumors larger than 7 cm. CONCLUSIONS: von Hippel-Lindau differs from sporadic renal cell carcinoma in morphology and biology. Our data provide arguments for planning surgery for von Hippel-Lindau renal cell carcinoma and should stimulate future investigations.

Adult↗
PubMed1997

Late occurrence of cysts in autosomal dominant medullary cystic kidney disease.

Medullary cystic kidney disease (MCD) is characterized by multiple renal cysts at the corticomedullary boundary area, by autosomal dominant inheritance, and by onset of chronic renal failure in the third decade of life. We report on a family with three affected individuals of both sexes in two generations presenting with end-stage renal failure at age 22-31 years. Primarily diagnoses considered included unclassified hereditary nephropathy and autosomal dominant polycystic kidney disease. Careful evaluation of all findings, initiated after investigation of renal morphology with CT, revealed features characteristic for MCD and led to the final diagnosis of MCD. We conclude that MCD is an important differential diagnosis for polycystic kidney disease in young adults with end-stage renal failure. Establishing the correct diagnosis has considerable impact for genetic counselling.

Adult↗
PubMed1997

Functioning thoracic paraganglioma: association with Von Hippel-Lindau syndrome.

Functioning thoracic paraganglioma (pheochromocytoma) is unusual and therefore suggestive of a pathogenesis distinct from that of sporadic adrenal pheochromocytoma. To determine whether the pheochromocytoma-associated syndromes Von Hippel-Lindau disease (VHL) and multiple endocrine neoplasia type 2 (MEN 2) play a role in the development of thoracic functioning paragangliomas, germline DNA from five unselected patients with this rare tumor was analyzed for mutations in the genes that predispose to VHL and MEN 2. Genetic investigations and further clinical data revealed that three had VHL, with two different germline mutations of the vhl gene, but no individual was affected by MEN 2. Two of the three patients with VHL did not show any additional VHL-associated lesions. This result suggests that VHL should be considered in the differential diagnosis of thoracic pheochromocytoma, as such a diagnosis carries further important implications for the patient and family. Conversely, in patients suspected of a catecholamine-secreting tumor and known VHL, thoracic localization should be considered if an adrenal pheochromocytoma cannot be detected.

Adolescent↗